From 4e8b0938d90793d6e1e200d6b25e6581b72bd4d0 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Wed, 20 Jun 2012 22:16:47 -0400 Subject: proper error handling for fcntl F_GETOWN on modern kernels on old kernels, there's no way to detect errors; we must assume negative syscall return values are pgrp ids. but if the F_GETOWN_EX fcntl works, we can get a reliable answer. --- arch/arm/bits/fcntl.h | 3 +++ arch/i386/bits/fcntl.h | 3 +++ arch/x86_64/bits/fcntl.h | 3 +++ include/fcntl.h | 11 +++++++++++ src/fcntl/fcntl.c | 10 +++++++++- 5 files changed, 29 insertions(+), 1 deletion(-) diff --git a/arch/arm/bits/fcntl.h b/arch/arm/bits/fcntl.h index fc65ebcc..9595f9ca 100644 --- a/arch/arm/bits/fcntl.h +++ b/arch/arm/bits/fcntl.h @@ -31,3 +31,6 @@ #define F_GETLK 12 #define F_SETLK 13 #define F_SETLKW 14 + +#define F_SETOWN_EX 15 +#define F_GETOWN_EX 16 diff --git a/arch/i386/bits/fcntl.h b/arch/i386/bits/fcntl.h index 7f09b95c..69f3a8f5 100644 --- a/arch/i386/bits/fcntl.h +++ b/arch/i386/bits/fcntl.h @@ -31,3 +31,6 @@ #define F_GETLK 12 #define F_SETLK 13 #define F_SETLKW 14 + +#define F_SETOWN_EX 15 +#define F_GETOWN_EX 16 diff --git a/arch/x86_64/bits/fcntl.h b/arch/x86_64/bits/fcntl.h index 7b300210..9e07229e 100644 --- a/arch/x86_64/bits/fcntl.h +++ b/arch/x86_64/bits/fcntl.h @@ -31,3 +31,6 @@ #define F_GETLK 5 #define F_SETLK 6 #define F_SETLKW 7 + +#define F_SETOWN_EX 15 +#define F_GETOWN_EX 16 diff --git a/include/fcntl.h b/include/fcntl.h index 36fb24bc..fcb622a2 100644 --- a/include/fcntl.h +++ b/include/fcntl.h @@ -99,6 +99,17 @@ int posix_fallocate(int, off_t, off_t); int lockf(int, int, off_t); #endif +#if defined(_GNU_SOURCE) +#define F_OWNER_TID 0 +#define F_OWNER_PID 1 +#define F_OWNER_PGRP 2 +#define F_OWNER_GID 2 +struct f_owner_ex { + int type; + pid_t pid; +}; +#endif + #if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE) #define open64 open #define openat64 openat diff --git a/src/fcntl/fcntl.c b/src/fcntl/fcntl.c index fa5ad32f..fb7806a3 100644 --- a/src/fcntl/fcntl.c +++ b/src/fcntl/fcntl.c @@ -1,6 +1,8 @@ +#define _GNU_SOURCE #include #include #include +#include #include "syscall.h" #include "libc.h" @@ -13,6 +15,12 @@ int fcntl(int fd, int cmd, ...) va_end(ap); if (cmd == F_SETFL) arg |= O_LARGEFILE; if (cmd == F_SETLKW) return syscall_cp(SYS_fcntl, fd, cmd, arg); - if (cmd == F_GETOWN) return __syscall(SYS_fcntl, fd, cmd, arg); + if (cmd == F_GETOWN) { + struct f_owner_ex ex; + int ret = __syscall(SYS_fcntl, fd, F_GETOWN_EX, &ex); + if (ret == -EINVAL) return __syscall(SYS_fcntl, fd, cmd, arg); + if (ret) return __syscall_ret(ret); + return ex.type == F_OWNER_PGRP ? -ex.pid : ex.pid; + } return syscall(SYS_fcntl, fd, cmd, arg); } -- cgit v1.2.1